Heretofore, it has been known to provide various types of powered brush devices for cleaning, polishing, scrubbing or the like. Such devices have formal application, for example, in cleaning, polishing, and scrubbing items including cuticles, jewelry, housewares (e.g. utensils), teeth or the like wherein there is a need to treat small and/or relatively inexcessible surfaces which are curved as well as flat. In cleaning teeth for example, prior powered tooth brushes have included tufts and bristles moved in a rotary, arcuate, reciprocating, or orbital path by a power mechanism and on larger paths by hand movement. Another design includes powered brushes in which the brush head is substantially stationary and individual tufts are mechanically rotated along their own axis but unidirectionally. Such prior powered brushes, for example, are disclosed in U.S. Pat. No. 2,215,031 to N. Elmore wherein the individual tufts of the brush head continuously rotate in one direction. Because of this unidirectional rotation, the individual tufts of these bristles tend to "run-out" of the crevices between large surfaces of teeth. In the mouth, the interproximal crevices and irregularly shaped openings make it difficult to insert the tufts of the brush into the crevices at right angles due to the curvature of the dental arch. This tendency to move out of a crevice or indentation impairs the cleaning efficiency of the toothbrush because the tuft is difficult to position within a crevice for an amount of time adequate to achieve removal of foreign matter deposited within the crevice.
In applicant-assignees prior U.S. Pat. No. 4,156,620, the electric-toothbrush disclosed includes means for rotating at least one tuft about its central axis in a controlled reciprocating manner whereby adjacent tuft is rotated a predetermined number of turns in one direction and then rotated a predetermined number of turns in the opposite direction relative to an adjacent tuft.
More specifically and as disclosed in said prior patent, in a preferred embodiment of the invention there is provided a plurality of tufts of filaments, and each of the tufts is rotated about its own axis in a controlled and predetermined manner. In particular, each tuft is rotated in a controlled reciprocal fashion and immediately adjacent tufts are counter-rotated. The tufts are rotated about their central axis in a first direction from a generally neutral position of maximum projected length to a position of maximum filament twist so that the projected length of the tuft diminishes and the tuft is stiffened for effective power transmission, and the tufts are reciprocally rotated about their central axis from the position of maximum filament twist. The last step of reciprocal rotation moves the filaments in each reciprocating cycle from a position of maximum twist in a first direction and a minimum projected length to a position of maximum twist in a second direction in generally the same minimum projected length, and then back to a position of maximum twist in a first direction and a minimum projected length while three times passing through a general neutral position of maximum projected length. This matter produces a sweeping action as well as a "pumping" action to force the tuft filaments into a positive gripping the work surface whether it be curved or flat resulting in an effective cleaning thereof.
As in said prior patent and to enable confining of the tufts on the work surface or, for example, within the interproximal crevices for a period long enough to attain thorough cleaning, each individual tuft is reciprocally rotated. In a periodontal application, for example, this rotation is commenced in one angular direction for a distance sufficient to produce both effective energy transfer and lateral movement of the tuft across the interproximal crevice to clean both approximal (mesial and distal) surfaces, but less than the amount which would give rise to "run-out" of the tuft and expulsion from the interproximal crevice. Then each tuft is rotated in the opposite angular direction, again just far enough to produce the same cleaning results with effective energy transfer while avoiding expulsion of the tuft from the work surface whether it be flat or curved, such as in an interproximal tooth crevice.
In the periodontal application of said prior patent, and in addition to the mesial and distal surfaces noted above, each tooth has a facial and a lingual surface, all four of which define the vertical surfaces of a tooth crown. Because the gingival margins of the interproximal crevices, usually defined by the interdental papilla, and the gingival margins of the raised facial and lingual tooth surfaces between the approximal surfaces are vertically staggered, the tufts are also preferably arranged in a staggered relationship in each row of tufts. A first set of long tufts may be positioned along a first line in the brush head and a second set of shorter tufts may be positioned along a second line in the brush head generally parallel to and spaced from the first line. Within this staggered arrangement, the long tufts reach into interproximal crevices of the teeth, and the shorter tufts clean the raised face areas of the teeth near the gingival.
Another desirable characteristic of the applicant-assignees prior patented brush is that there is reduced vibratory movement of the brush head itself. Therefore, the brush head can be moved slowly and gently over the tooth surfaces and adjacent gingiva. The entire head of the brush does not oscillate, rotate, move in circular or elliptical paths, or become involved in any movement other than that imparted by the user. This characteristic is particularly important in cleaning teeth because the amount of cleaning motion that can be imparted to a moving brush head cannot be large enough to cause so-called "cheek shake" by action of the brush head in moving against the inner surfaces of the cheek.
In the dental field and for reference to prior manual and/or electric toothbrush devices, attention is brought to the following patents:
______________________________________ U.S. Patent Documents ______________________________________ 793,587 2,682,066 1,476,433 2,799,878 1,557,244 3,103,679 1,712,579 3,178,754 2,140,307 3,242,516 2,215,031 3,400,417 2,598,275 3,577,579 ______________________________________
______________________________________ Foreign Patent Documents ______________________________________ 634,607, Germany, 8/1936 2,263,432, Germany, 5/1974 1,114,464, Germany 10/1959 480,510, Italy, 3/1954 2,215,799, Germany 10/1972 1,081,021, United Kingdom, 8/1967 ______________________________________
Other patents and/or publications known to applicant will be made of record under applicants' Prior Art Disclosure Statement.
Accordingly, though prior automatic-type toothbrushes have been referred to by way of example, it is to be understood that these and other related problems in the cleaning of teeth also may be present in other cleaning, polishing, scrubbing or like applications. Such may be case with workpieces, such as cuticles, jewelry, housewares, or the like, particularly in cleaning applications where brush accessibility and/or brush "run-out" is a problem.